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Discussion Starter · #21 ·
I am back into this project. I have just opened the wring compartment and I am a bit shocked by the gage of the wires inside. L1 to the thermostat, is AWG 14. L2 is 3.13mm2 which I don't think it gets to AWG 12. There are plenty of 16s going from the wattage terminal board to the heating element, but those may feed in parallel for highest power.
I have seen comments online about wires burning and having to replace them.

I know some of you guys,@Missouri Bound, @rjniles, have been running this heater for a while... Did you notice the gauges? Have you opened it to to see if the wires are toasty?

Just wondering if I should replace the first two segments of L1/L2 with plain THHN. I realize THHN is rated for 90C, instead of the 125C it has, but at least bigger gauge.
 

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I am back into this project. I have just opened the wring compartment and I am a bit shocked by the gage of the wires inside. L1 to the thermostat, is AWG 14. L2 is 3.13mm2 which I don't think it gets to AWG 12. There are plenty of 16s going from the wattage terminal board to the heating element, but those may feed in parallel for highest power.
I have seen comments online about wires burning and having to replace them.
I wouldn't worry about that. The contents of a product are the domain of UL, and must meet the standards specified in the UL White Book. That specifically allows smaller wires in enclosures, because thermal management inside an engineered enclosure is a different subject than inside a wall packed in insulation. Make sure it complies with the White Book by making sure it has a UL, ETL or CSA mark with a file number.

Besides, those wires probably have higher temp insulation than THHN.

And it's not like the heat is being wasted.


Just wondering if I should replace the first two segments of L1/L2 with plain THHN. I realize THHN is rated for 90C, instead of the 125C it has, but at least bigger gauge.
Or you could order >=125C wire from McMaster-Carr or Grainger.
 

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Discussion Starter · #23 · (Edited)
One more related question. I need to install a 24V transformer for the thermostat of this heater. In the future, I may have need for 24V on another thermostat for heat pump. Is it common to share these transformers over multiple circuits? My guess is that a 25-40VA transformer would have no problem handling both.

If I go with a single, then I should probably hook the transformer to the lights circuit and hub-install it double tap on the sub panel. If dedicated, then I may hub-mount it on the same box as I will have an RIB 30A and the SOOW 10/4 going to the heater. Then I would try to find one with the high and low voltage on the same hub.

About the transformers with hubs, are they normally compatible with the wall offset of the KOs on any metal boxes?
 

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Discussion Starter · #25 ·
Surely there must already be a 24V transformer on the heater. How does it fire now?
No. It has a small built in mechanical thermostat, knob on the front, that closes contact. It is a common FUH54. I am going to install an external electronic thermostat/transformer/relay. I could install a line thermostat, but months ago when I posted, the suggested solution was the 24V solution.
 

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Discussion Starter · #26 ·
I think the easy way is to install the transformer in a 1/2 KO in the sub panel. Thanks
 

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Let us know how this turns out. I have two of the 3000 watt 220v wall heaters in different rooms of my house. They have the little mechanical knob on front of them which is lame, but does work. After a while mine is starting to get loose.

Would like a different option to adjust temp on them. They are really great powerful heaters.
 
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